1. Field of the Invention
The present invention relates to a keyboard apparatus. In particular, the present invention relates to a keyboard which can be adjusted to vary the size of the keyboard, the spacing between the keys, and the size of the keys of the keyboard.
2. Description of the Prior Art
For the input of information into computer based equipment (with word processing as a prominent example), typing remains the dominant mode of translating the brain""s perception of the desired textual information into a processable data stream of digital information. While touch typing using all of the fingers is the fastest and most often used input system, many information system users successfully input information using only one or two fingers.
Speech recognition systems are becoming more usable, but depend on having a great deal of computer information processing power available to interpret the spoken word and recognize the probable written word form that the sounds represent. Powerful full size laptop or desktop computers are needed to provide the signal processing capability required for even moderately accurate voice recognition. At this time, the voice recognition system must be trained to recognize the voice pattern for a particular speaker, generally using standardized text materials which the prospective speech recognition user must vocalize in training sessions.
Noise cancellation microphones, correctly placed near the mouth are generally needed to improve the quality of the voice signal that serves as input to the speech recognition system so as to avoid recognition mistakes. The user must usually have a nearby keyboard available to reinstruct or correct the voice recognition system when errors in recognition occur, or if new, possibly complex, words are to be added to the speech recognition library.
Thus, for the near term future, touch typing, using all fingers or just one or two, will remain the most common information input system.
As the use of the internet for email messages or information browsing grows and computer technology provides sufficient information processing power for devices smaller than a standard laptop computer, the desire to use small portable xe2x80x9cpalm-topxe2x80x9d information handling devices for messaging grows very rapidly. Most of these small portable information handling devices use a miniature xe2x80x9cQWERTYxe2x80x9d alphanumeric keyboard. For information retrieval and entry, the user must use the eraser end of a pencil or a carefully placed fingertip to correctly actuate the very small key button tops.
While the small keyboards on portable devices can be used to enter information, most people do not find it convenient to put in messages of over one paragraph by pressing the tiny key buttons. Thus, there is a need to make the tiny keyboards xe2x80x9cgrowxe2x80x9d in size to accommodate easy finger typing, and hopefully, even xe2x80x9ctouch typingxe2x80x9d. There are alternative input systems to keyboards, such as the use of a stylus to write on a xe2x80x9ctouch screenxe2x80x9d, but thus far, the handwriting or stroke input recognition systems are somewhat inaccurate or slow, so that again, only brief message inputs are practical.
Proposals for compressing and then growing a keyboard in size have previously been made. U.S. Pat. No. 5,141,343 to Roylance et al. teaches a physically expansible/compressible keyboard. That patent discloses key buttons which are the same size as key buttons on a full-size keyboard in which the pitch spacing (center to center dimension between adjacent keys) is variable. Thus Roylance teaches tight packing of the keyboards during device transport, opening out to a usable keyboard during use. The use of key buttons that are the same size as full size key buttons on a standard keyboard limits the size compression. Therefore, the Roylance keyboard is not well suited for really small, fully portable handheld devices, such as those that are markedly smaller than a standard laptop computer. Furthermore, the Roylance device uses a complicated mechanical apparatus to move the keys, increasing manufacturing difficulty and cost.
U.S. Pat. No. 3,940,758 to Margolis discloses a keyboard with several hinged sections. The hinged sections are folded for transport and unfolded for use. While this does achieve a compact transportable device, the stacked sections do not allow the user to have access to the keyboard when compressed. For many short transactions, it is preferable for the user to do single keystroke data input on the fully compressed keyboard, and only expand the keyboard to a larger size when longer data input is required. This function allows the device user to conveniently operate the device in crowded situations, such as in a telephone booth, or during a ride on a bus, taxi, train, plane or commuter van. When the rider reaches the destination, the device can then be expanded for typing convenience during longer data input sessions. For even more convenience, the ultra miniature keyboard, when in expanded mode, may split into two portions and provide fixed or variable angulation, as described in U.S. Pat. No. 4,661,005 to Lahr. The splitting reduces the need for wrist pronation or other xe2x80x9ccontortionsxe2x80x9d to use a small size keyboard.
U. S. Pat. No. 5,938,353 to Butler presents the use of key tops which have only one size, but have serrated edges which can interlock together to provide compression in size during compacted form, and teaches the use of handles and detents to aid opening and closing of the serrated key button keyboards between their compacted and expanded sizes. Single section key buttons are a limiting design factor in how compact the keyboard can be made in its compressed state. Multi-section key buttons provide more design flexibility and potentially more potential compression compared to the expanded format keyboard. Also, when the serrated edge key buttons are placed in their compacted form, it may be more difficult to use them xe2x80x9cas isxe2x80x9d to perform limited data input. Ideally, the user should be able to choose which keyboard mode to use: compacted for ease of travel with no xe2x80x9cchangeoverxe2x80x9d efforts for limited data entry, or expanded, for ease in typing of longer documents.
Other means of providing a more convenient keyboard format for longer typing sessions include attaching either a single large keyboard to the smaller data handling device, or in some cases, providing an external two or three section keyboard which can be compacted to make the transport size smaller. Again, these devices do not provide the user with the combination use of a smaller keyboard format for quick typing input, and a larger format for longer typing sessions.
Thus, what is needed is a miniature keyboard in which the key button size as well as the keybutton pitchxe2x80x94i.e. distance between the keys xe2x80x94can grow. The user can utilize xe2x80x9cone key at a timexe2x80x9d data input operation when the miniature keyboard is compacted to its smallest size, but has the option of physically expanding the keyboard to achieve xe2x80x9ctouch typingxe2x80x9d ease when working with longer data documents. By compacting the key button size as well as the pitch, it is possible to achieve a tiny keyboard for portability, but retain the dual input mode options: (1) one-a-time pressing of the compacted key buttons for limited data input or (2) expansion to a nearly full sized keyboard for more convenient input of longer information segments by touch typing as for creating a one or two page email message for transmission.
In accordance with the invention, a keyboard with a housing which may be extended from a contracted to an expanded state is provided. A plurality of elastic belts is attached to the housing, and key switch assemblies are fastened to the elastic belt. When the housing is extended, the elastic belts stretch. Correspondingly, the key switch assemblies move apart, thereby increasing the key pitch and providing an expandable keyboard.
In another embodiment, expandable keytops are mounted to the elastic belt. When the keytops are pressed, they activate the key switch assemblies. The keytops may be made of an expandable material so that they expand and contract as the elastic belt expands and contracts.
Further objectives and advantages of the subject invention will be apparent to those skilled in the art from the detailed description of the disclosed invention.